The invention generally relates to a releasable cord clamping or closure device, and more specifically to a spring actuated cord closure having a plunger with a throughhole reciprocatingly disposed and retained in a housing cavity with a hole through opposing sides wherein the spring is initially retained in compression on the plunger to facilitate alignment of the holes in the cord closure for threading the cord therethrough without the spring urging the plunger away from the housing.
Releasable cord fastening devices have many well known applications including the fastening of draw strings on sleeping bags, backpacks, jacket hoods, wastebands, and other garments resulting in enormous success in the market place. The device typically includes a plunger with a throughhole reciprocally disposed and retained in a housing cavity with holes through opposing sides thereof wherein a bias spring urges the plunger away from the housing to engage and securely retain a cord threaded through the throughhole of the plunger and the holes of the housing. The cord is released by depressing the plunger relative to the housing against the bias of the spring to align the holes thereby permitting the cord to be drawn or threaded without obstruction through the holes. Initial threading of the cord through the holes of the device likewise requires depressing the plunger relative to the housing to align the holes. Not unexpectedly, repeated manual depressing or actuation of the fastening device for threading the cord through the holes as in a garment or other production line is painstaking work which gives rise to muscle fatigue and is a suspected cause of debilitating maladies like carpel tunnel syndrome.
To overcome the problems resulting from repeated manual actuation of the cord fastening devices or closures, prior an cord closures have provided a sub-assembly including a plunger with a retaining member which initially retains the spring under compression on the plunger so that the plunger can be freely positioned relative to the housing to align the holes of the closure device without the spring urging the plunger away from the housing. FIG. 5a. is a side view of an unassembled prior art cord closure sub-assembly and housing including a plunger 1, a cylindrical helical coil spring 2 and a retaining member 3. FIG. 5b is a side view of an assembled prior art sub-assembly disposable in a housing 4. The bias spring is disposed about a stem 5 on the plunger 1 and one end of which is seated on a neck 6 of the plunger whereabout the spring is preferably fictionally retained to secure the spring during assembly. An opposing end of the spring is seated on a shoulder 7 of the retaining member, which preferably has a collar for centering and frictionally retaining the spring during assembly, and the retaining member is disposed over and seated on shoulders 8 of resilient prongs of the stem to retain the spring in compression on the plunger. FIG. 5c is a side view of the prior an cord closure of FIG. 5a wherein the spring is retained under compression on the plunger by the retaining member so that holes in the plunger and housing may be readily aligned without influence from the spring to permit threading of a cord through the aligned holes of the cord closure. The spring is released from the plunger by depressing the plunger to drive the resilient prongs into a bore in a closed end of the housing. Edge portions of the bore urge the resilient prongs toward each other to permit the retaining member and spring to pass around the prongs and to seat on the closed end of the housing wherein the compressed spring urges the plunger away from the housing to engage and retain the cord.
The prior art cord fastening device or closure however has many disadvantages including the additional cost of the retaining member and assembly thereof. Further, assembly of the spring about the stem of the plunger and retaining of the compressed spring thereon with the retaining member is a tedious assembly procedure due to the tendency of the spring and the retaining member to separate from the plunger. This problem can be overcome in part by frictionally retaining one end of the spring about the neck of the plunger and the other end of the spring about the collar of the retaining member, but this solution requires additional structure on the plunger and on the retaining member, namely the neck and the collar, resulting in still higher costs, and does not always prevent separation of the components. Moreover, the dimensions of the retaining member and prongs must be made to within narrow tolerances to ensure reliable release of the compressed spring from the plunger further increasing the expense of the device.
In view of the discussion above, there exists a demonstrated need for an advancement in the art of cord fastening or closure devices. It is therefore an object of the present invention to provide a novel cord closure.
It is another object of the invention to provide a novel cord closure with a compressed spring retained on a plunger to form a sub-assembly which is reciprocally disposable in a cavity of a housing so that a throughhole in the plunger may be readily aligned with holes in the housing without influence from the bias spring to permit threading of a cord through the aligned holes of the cord closure.
It is a further object of the invention to provide a novel cord closure that is economical, requires fewer components, is relatively simple to assemble, and is reliable.
Accordingly, the present invention is directed toward a novel cord closure comprising a housing having an open end, a surrounding side wall and a closed end which forms a cavity for receiving a plunger. The plunger has a body with a throughhole which is alignable with holes formed through opposing sides of the surrounding side wall of the housing. The plunger also has a stem extending from a shoulder portion of the body and has a resilient retaining member on a distal end portion away from the body. A bias spring is disposed about the stem of the plunger and is releasably retained in compression on the plunger between the shoulder portion of the body and the resilient retaining member. At least a portion of the body and the stem of the plunger are reciprocally disposable in the cavity so that the throughhole of the plunger is alignable with the hole formed through opposing sides of the housing to permit threading of a cord through the aligned holes of the cord closure without the bias spring urging the plunger away from the housing. The housing includes a release means disposed in the closed end of the cavity for engaging the resilient retaining member to release the bias spring from the releasable retaining member when the plunger is depressed into the cavity of the housing whereafter the bias spring urges the plunger away from the housing to engage and retain the cord threaded through the holes of the cord closure. In one embodiment, the resilient retaining member includes a pair of resilient prongs having a shoulder portion wherein the bias spring is releasably retained in compression on the plunger between the shoulder portion of the body and the shoulder portion of the resilient prongs. The bias spring is a helical coil spring with at least one tapered end which is seated on the shoulder portion of the resilient prongs when the bias spring is releasably retained in compression on the plunger. The resilient prongs may each have a bevelled outer side portion and a flange on an inner portion of the shoulder for aligning the bias spring on the shoulder portion of the resilient prongs when the bias spring is retained in compression on the plunger. In one embodiment, the release means is a bore in the closed end of the cavity with edge portions engageable with an outer side portion, preferably bevelled outer side portions, of the resilient prongs to urge the prongs toward each other for releasing the bias spring from the shoulder portion of the resilient prongs when the plunger is depressed into the cavity of the housing.
These and other objects, features and advantages of the present invention will become more fully apparent upon consideration of the following Detailed Description of the Invention with the accompanying drawings in which like structure and steps are referenced by corresponding numerals and indicators.